Water is becoming scarcer, especially in developing countries. As a result, there is need to save water in as many ways as possible.
Foam is usually associated with cleaning products such as laundry detergent compositions and dishwash compositions. Products that foam copiously during the pre-rinse cleaning stage, or in other words, the ones which have greater foaming ability, are perceived to be better than the ones that foam less. Consumers do prefer products that foam copiously. On the other hand, it is also necessary to rinse the articles with clean water so that the foam subsides. Most consumers tend to rinse until there is no visible sign of foam and usually four to five rinse-cycles is the norm. However, such a practice is not sustainable because substantial amount of fresh water is necessary for each rinse-cycle. Therefore there is need for compositions which foam copiously during pre-rinse stage, but which could be rinsed off with minimal water.
Conventional antifoam agents like silicones and soap are good defoamers but they affect the foam volume during pre-rinse stage.
WO9827189 A1 discloses a mildly acidic laundry detergent composition containing rinse-activated antifoam ingredients. The composition has an anionic surfactant and/or at least one non-ionic surfactant. Also present is a rinse-active, pH sensitive, foam control agent which comprises a fatty acid. Upon rinsing, at least a portion of the fatty acid converts into soap to suppresses the foam. The fatty acid may be saturated or unsaturated and preferably is lauric, myristic, oleic, stearic, palmitic or tallow fatty acid. Even fatty acids are used as antifoam agents.
US2015/0191676 A1 (P&G) discloses a liquid laundry detergent composition containing an alkyl ethoxy sulphate surfactant along with two or more fatty acids characterized by a specific fatty acids distribution profile as rinse-activated antifoam agents. The composition contains 0.1 wt % to 4 wt % of two or more fatty acids or salts where C14 component forms 30% to 90% of the total fatty acid content.
Our co-pending unpublished European application EP 14182852.5 (Unilever) discloses a dishwash composition containing rinse-activated antifoaming system containing lauric acid and stearic acid.
U.S. Pat. No. 3,919,111 B1 (Henkel, 1975) discloses foam-control using mono or diester of hydroxystearyl alcohol with a saturated fatty acid or hydroxy fatty acid having from 15 to 24 carbon atoms dispersed in an organic solvent or water.
US2014/0323386 A1 (The Nisshin Oillio Group Ltd) discloses the use of polymerised hydroxyl stearic acid and an esterification reaction product of the polymer in detergent products for rinse-activated foam control.
While fatty acids are used for rinse benefits, i.e., in order to reduce the number of rinse-cycles, any indiscriminate increase in their amount is counterproductive. In particular, the use of fatty acids may render the compositions unstable and such compositions are prone to phase separation.
In one publication, WO2013160265 A1 (Henkel), hydroxyl fatty acids are used as foam stabilisers.
Therefore there is an unmet need for compositions which have more efficient rinse-activated antifoaming system.
It is an object of the present invention to provide a cleaning composition, especially a dishwashing composition, which provides high foam-volume during the washing or the pre-rinse stage but which requires lesser than the usual number of rinse-cycles for the foam to subside.
It has been determined that the object can be met by a rinse-activated antifoaming system comprising a hydroxy fatty acid and a non-hydroxy fatty acid.